Quoted By:
>Dex entries are now as long as they were in RSE again
>You can hear your footsteps when you start running, and can also hear your footsteps when walking on metal flooring (a good example of this is the single metal strip in the boat lab in Slateport)
>Some Pokemon now have intro animations, but only when found in the wild
>Almost every house has unique objects scattered around it in different ways
>Tons of weird and funny NPCs (...that Nugget guy in Mauville)
>Generic wild Pokemon now appear in the overworld (Wingull at Route 104, Swablu at Route 114)
>The bike light which turns on at night automatically turns off if you get close to an NPC, so you don't blind them
This is just the stuff off of the top of my head, but there's a lot of cool stuff done to make Hoenn feel alive. It's like comparing DP to HGSS, and I love it.